Radio receiving apparatus



E. BELLINI RADIO RECEIVING APPARATUS Filed June 3. 1927 Jan. 20', 1931.

INVENTOR moan mum ATTORNEY Patented Jan. 20, 1931 UNITED s'r'rss PATT ()FFICE ETTORE IBELLINI, F PARIS, FRANCE, ASSIGNOR TO SOCIETE FRANGAISE RADIO ELEC- TRIQUE, 0F PARIS, FRANCE, A JOINT-STOCK COMPANY OF FRANCE RADIO nnonrvnve AIEPARATUS Application filed June 3, 1927, Serial No. 196,379, and in France June 4, 1926.

This invention relates to improved receiving and transmitting systems and more particularly to such systems wherein means is provided for eliminating atmospherics or strays.

The inconvenience occasioned in radio reception by atmospheric or industrial stray currents and influences has been known for a long time.

The present invention has for one of its objects the elimination or substantial reduction of these two kinds of stray action.

The receiver apparatus, comprising a radio frequency amplifier (amplification before detection), consists essentially in disposing between two grids or between two plates, or

between a gridand a plate, in radio frequency amplifier tubes (the stage of which is conveniently selected tentatively or experimentally), a stopper circuit which is to be tuned to the wave-length to be received.

This circuit is thus equivalent to a break or to a very high impedance for the wave to be received, and this allows the amplifier to continue operating. And it also is equivalent tea more or less complete or dead shortcircuit for all of the other waves which will be neither amplified nor received.

In the accompanying drawing,

Figure 1 shows the stopper circuit a inserted between the grids of the second and third stage.

Figure 2 shows the stopper circuit taken oil 7 between the plates of the first and the third tube.

Figure 3 shows the stopper circuit connected between the plate of the detector tube and the grid of the second tube.

In Figure 3, A is a blocking condenser of 49 high capacity which serves to maintain the mean potentials of the plate and the grid at the desired'values.

If the grid of the detector tube comprising a shunted condenser is to be used, then the stopper circuit should not be connected directly with the grid, but rather ahead of the shunted condenser, in a manner indicated at m in Figure 1.

Circuit arrangements of this kind may be adopted in transmitter stations for the objeet of suppressing noises of all sorts liable to be superposed upon the radiations from the station.

They are likewise useful for suppressing supply-line noises, if the radio frequency amplifiers are fed from a supply network.

They could also be used in amplifier stages handling intermediate frequencies, in receiving apparatus based upon the principle of graduated frequency reduction of the radio transmission '(super-heterodyne, radio modulators, etc.)

Having thus described my invention, I claim:

1. A circuit arrangement for eliminating atmospherics or strays, comprising a plurality of vacuum tube amplifiers, and a tuned parallel resonant circuit tuned to the received wave connected between two electrodes other than cathodes, each of said electrodes being associated with a difierent amplifier.

2. A circuit arrangement for eliminating atmospherics or strays, comprising a plurality of stages of radio frequency amplification, and a tuned parallel resonant circuit tuned to the received wave connected between two elements, each associated with a different stage.

3. A circuit arrangement for eliminating atmospherics or strays, comprising a plurality of stages of radio frequency amplification, and a tuned parallel resonant circuit tuned to the received wave connected between the grids of two stages.

4:. A circuit arrangement for eliminating atmospherics or strays,comprisinga plurality of stages of amplification, and a rejector circuit tuned to received signal Waves connected between similar electrodes of successive stages. 

